Generator of absorption refrigeration apparatus

ABSTRACT

A generator of an absorption refrigeration apparatus having a pumping chamber to which a rich refrigerant solution is supplied from an absorber, and above which a boiler tube is vertically disposed in vertical alignment with the pumping chamber, with the boiler tube being connected at its top to a condenser via a vapor-liquid separator. A vapor lift tube extends from the pumping chamber upward into the boiler tube to open at its top within the tube. The boiler tube and pumping chamber are provided on their sides with dual heating a device for heating refrigerant solution in the tube and chamber. The arrangement of the parts is such that a compact general configuration of the generator is afforded.

United States Patent Ando et al.

[ 5] Mar. 14, 1972 [54] GENERATOR OF ABSORPTION REFRIGERATION APPARATUS[72] Inventors: Tsuneo Ando, Gifu; l-lironori Nakashima,

Aza-Koyamanishi, both of Japan [73] Assignee: l-lowa Sangyo KabushikiKaisha, Sakurada-cho, Atsuta-ku, Nagoya-shi, Aichiken, Japan [22] Filed:'June9, 1970 [21] Appl. No.: 44,749

[30] Foreign Application Priority Data June 13, 1969 Japan ..44/46l28[52] 0.8. CI ..62/236, 62/490, 62/496, 62/497, 219/279, 219/536 [51]Int. Cl ..F25b 27/00, F25b 33/00 [58] Field ofSearch ..62/ll0, 148, 236,490, 495, 62/496, 497; 219/279, 535, 536

[56] References Cited UNITED STATES PATENTS 2,977,775 4/ 1961 Tamada etal. ..62/497 TO ABSORBER COIL 2,999,373 9/ 1 961 Stierlin ..62/4973,253,421 5/1966 Grubb... ...62/148 2,797,555 7/1957 Kogel ..62/4903,243,572 3/1966 Vogt et al. 219/536 X 3,130,564 4/ 1964 Cronelia etal... 62/490 X 3,177,677 4/1965 Boren et al... 62/148 X 3,225,560 12/ 1965 Doebeli ..62/236 Primary Examiner-William F. ODea AssistantExaminer-P. D. Ferguson Attorney-Holman & Stern [57] ABSTRACT Agenerator of an absorption refrigeration apparatus having a pumpingchamber to which a rich refrigerant solution is supplied from anabsorber, and above which a boiler tube is vertically disposed invertical alignment with the pumping chamber, with the boiler tube beingconnected at its top to a condenser via a vapor-liquid separator. Avapor lift tube extends from the pumping chamber upward into the boilertube to open at its top within the tube. The boiler tube and pumpingchamber are provided on their sides with dual heating a device forheating refrigerant solution in the tube and chamber. The

arrangement of the parts is such that a compact general configuration ofthe generator is afforded.

5 Claims, 3 Drawing Figures TO CONDENSER Patented March 14, 1972 2Sheets-Sheet 1 TO CONDENSER FIG.

TO ABSORBER COIL INVENTORS 7M; M

ATTORNEY;

l ,I? l v I BY GENERATOR OF ABSORPTION REFRIGERATION APPARATUSBACKGROUND OF THE INVENTION This invention relates to absorptionrefrigeration apparatus and, more particularly, to a generator of anabsorption refrigeration apparatus of the type employing two cylindricalheating devices on the side wall of a boiler of the generator.

In conventional generators of absorption refrigeration apparatus, thereare usually provided separately a boiler for a refrigerant solution anda pumping or vapor lift tube. The boiler and tube are usually joined tothe side wall of a heating device in heat exchange relationship thereto.Because the boiler andlift tube are separately disposed around theheating device, considerable space is needed for the generator.Furthermore, because the vapor lift tube extends upwards along theheating device and is thereafter bent toward the boiler so as to bejoined therewith, the pumping or vapor lifting action is not soeffective and the general configuration of the generator is relativelyirregular, which is the cause of the generator assembly being unstablein construction and operation. These problems are more serious with agenerator having two heating devices, such as one having selectivelyusable gas and electric heating devices.

SUMMARY OF THE INVENTION In view of the above described circumstances,it is an object of the present invention to provide a novel generator ofan absorption refrigeration apparatus, which is superior in the pumpingor vapor lifting function to the conventional ones.

Another object of the invention is to provide a novel generator of anabsorption refrigeration apparatus, which is compact in generalconfiguration and therefore stable in construction and operation.

Still another object of the invention is provide a generator of the typeincluding selectively operable dual heating devices, in which heattransfer from the heating devices to the refrigerant solution in thegenerator is more intense at lower parts of the generator than at upperparts of the same.

In accordance with the present invention, briefly stated, there isprovided a pumping chamber below a boiler tube, into which a vapor liftpipe of a smaller diameter extends upwards from the pumping chamber insubstantially coaxial relationship to the boiler tube so as to open intoan upper space within the tube. On the side surfaces of the chamber andtube, there are secured heating devices for heating a refrigerantsolution within the generator. Because the vapor lift tube passes withinthe boiler tube, hot refrigerant and its solution, while flowing upwardsthrough the lift pipe, give their heat to a weak solution surroundingthe lift pipe to heat the same from inside in addition to the heat fromoutside the boiler tube. It will be appreciated that such dual heatingwill improve the refrigerant vapor expelling function in the generator.It will also be appreciated that the provision of the vapor lift pipewithin the boiler tube makes the general arrangement of the partscompact and stable.

The foregoing and other objects, as well as advantageous features of theinvention will become more clearly apparent from the following detaileddescription with respect to preferred embodiments of the invention, whenread in conjunction with the accompanying drawing, in which like partsare designated by like reference numerals and characters.

BRIEF DESCRIPTION OF THE DRAWING FIG. 2, but showing a modified ar-DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanyingdrawing, the generator shown and generally designated therein byreference character G is incorporated in and constitutes an importantcomponent of an absorption refrigeration apparatus, the essentialcomponents of which, other than the generator G, are known and includean absorber including an absorber vessel 11, a heat exchanger 9, anabsorber coil (not shown), a condenser (not shown), an evaporator (notshown) etcetera.

The generator has a pumping chamber 1 and a boiler tube 2. The pumpingchamber 1 may be in the form of a vertically extending tube of the samediameter as that of the boiler tube 2 and is in axial alignment with thetube 2. The interior of the chamber 1 is in communication with theinterior of the boiler tube 2 through a vapor lift pipe 4 extendingupwards into the boiler tube 2 to terminate at its open upper end in theupper interior of the latter. It will be noted that the chamber 1 andthe tube 2 are rigidly connected by means of the pipe 4.

An upper end part 2a of the boiler tube 2 is connected to an upper partof a vapor-liquid separator 3 which is also in the form of a verticallyextending tube. A conduit 3a leading at its upper part to the condenser(not shown) extends downward at its lower part into the separator 3 andhas its lower end open to the interior of the separator 3 near the lowerend thereof.

A gas-heating flue 5 extends vertically and parallel along and is weldedat 7 to the side walls of the pumping chamber 1 and the boiler tube 2.The welds 7 are made denser or thicker in the downward direction so thatbetter heat exchange is obtainable between the gas-heating flue 5 andthe pumping chamber 1 than between the gas-heating flue 5 and the boilertube 2, and that better heat exchange is obtainable at lower parts ofthe boiler tube 2 than at upper parts of the same.

An electrical heating sleeve 6 extends vertically and parallel along andis welded at 7a to the side walls of the pumping chamber 1 and theboiler tube 2. The welds 7a therebetween are also made denser or thickerin the downward direction so that better heat exchange is obtained atlower parts than at upper parts. The arrangement of the electricalheating sleeve 6 relative to the gas heating flue 5 is best shown inFIG. 2, from which it will be noted that the electrical heating sleeve 6and the gas-heating flue 5 are on diametrically opposite sides of thepumping chamber 1 and boiler tube 2, and that a plane passing throughthe longitudinal axes of the flue 5 and sleeve 6 is perpendicular to aplane passing through the longitudinal axes of the boiler tube 2 andseparator 3.

A rich or strong solution transfer conduit 8 connects the bottom of theseparator 3 to a lower part of the pumping chamber 1. As is shown inFIG. 2, the conduit 8 extends in the plane passing through thelongitudinal axes of the separator 3 and the chamber 1.

A lower part of the boiler tube 2 is in communication with the heatexchanger 9 through a lean or weak solution transfer conduit 10. It willbe noted from FIG. 2 that the beginning or upstream end portion of theconduit 10 extends in the same plane passing through the axes of theseparator 3 and the chamber 1. From the foregoing, it will beappreciated that the structure including the generator assembly G, andthe associated conduits are in a compact and symmetrical arrangementand, therefore, are stable in structure and in operation.

From the absorber vessel 11 extends a rich liquid conduit 12 whichpasses through the heat exchanger 9 and is led to a lower part of theseparator 3.

The gas heating flue 5 contains therein a baffle 14 for improving heattransfer. Under the flue 5, there is provided a gas burner 13.

The electrical heating sleeve 6 is formed with a longitudinal slit l6and made of a resilient material such as a steel sheet. Within thesleeve 6 there is disposed a cartridge-type electric heater 17 which isresiliently gripped by the sleeve 6 and in tight engagement with thesame so as to establish a heat exchange relation between the sleeve 6and the heater l7.

FIG. 3 shows a modified arrangement of the generator assembly G, inwhich the gas heating flue and the electrical heating sleeve 6 aredisplaced in a direction remote from the separator 3. It is to be notedthat in this modification, the plane passing through the longitudinalaxes of the flue 5 and the sleeve 6 remains substantially perpendicularto the plane passing through the axes of the boiler tube 2 and theseparator 3. It will be understood that this modification also affordscompactness and stability.

The generator of the above described organization according to theinvention, incorporated within an absorption refrigeration apparatus,operates in the following manner when heated by gas by the gas burner13.

Hot combustion gas produced by the burner 13 flows upwards through theflue 5, and the heat in the gas is intercepted by the baffle 14 andtransferred across the wall of the flue 5 and then across the walls ofthe boiler tube 2 and the pumping chamber 1 into the liquids therewithinso as to heat the latter.

in this case, since the welds between the flue 5 and the pumping chamber1 are dense, an effective heat transmission is carried out through thewelds so that the solution rich in refrigerant, such as dense ammoniawater, is boiled in the boilin'g chamber 1 to expel the refrigerantdissolved therein. The refrigerant gas thus expelled is accumulated asbubbles in the upper part of the boiling chamber and caused to flowupwards through the lift pipe 4 in a condition in which it is intermixedwith steam and water so as 'to be supplied into the boiler tube 2through the upper opening of the pipe 4.

It is to be noted that since the lift pipe 4 is of small diameterrelative to that of the pumping chamber 1, a strong upward flow of theexpelled refrigerant and the intermixed boiled water is created throughthe lift pipe 4 with an intense pumping action.

The refrigerant and the water intermixed therewith, supplied into theboiler tube 2, then enter the vapor-liquid separator 3, in which therefrigerant gas is separated from the water and thence flows through theconduit 3a to the condenser (not shown) of the refrigeration apparatus.

On the other hand, a weak solution is accumulated in the boiler tube 2and receives heat from the gas heating flue 5 throughthe welds 7 andfrom the fluid flowing through the pipe 4, whereby the weak solution inthe boiler tube 2 is also boiled so as to liberate refrigerantadditionally therefrom. The weak solution accumulated in the boiler tube2 flows through the weak solution transfer conduit 10 into the heatexchanger 9 and is passed by means of a conduit 9a to the absorber coil(not shown).

The refrigerant which has condensed in the condenser is thereaftersupplied into the evaporator (not shown) to be evaporated therein. Theevaporated refrigerant flows into the absorber vessel 11 through aconduit 11a and is directed through a conduit 11b to the absorber coilto be absorbed into the weak solution which is supplied to the absorbercoil through the pipe 9a.

The liquid enriched in refrigerant within the absorber coil flows downinto the absorber vessel 11 through the conduit llb and is accumulatedin the vessel as is well known in the art.

In the bottom of the separator 3, there is accumulated a weak solutionfrom which refrigerant gas has been liberated. The rich solution in thevessel 11 flows through the rich solution transfer conduit 12 into theheat exchanger 9 and exchanges heat with the hot weak solution from theboiler tube 2 to be heated, thereafter entering the separator 3 to bemixed with the liquid existing within the same. The rich solution thenflows into the pumping chamber 1 through the conduit 8. Since theconduit 8 opens into the pumping chamber 1 at a low part of the latter,a good heating effect of the liquid is obtained within the chamber 1.The boiled liquid in the chamber 1 liberates the refrigerant andperforms the same function as described hereinbefore.

in the operation of the apparatus through the use of the electricalheating device, the electric heater I7 is ener zed and the heat therebyproduced in the heater IS tran erred through the sleeve 6 and welds 7 tothe solution within the pumping chamber 1 and boiler tube 2, in whichthe solution is heated in the same manner as described hereinbefore andperforms the same function.

While the invention has been described above with respect to preferredexamples, it will be understood that the invention may be carried out inother forms without departing from the scope of the invention.

We claim:

1. In an absorption refrigeration apparatus including a generator havingvertically elongated refrigerant solution boil ing means provided withcylindrical electric and gas heaters disposed therealong, said generatorincluding a vapor-liquid separator communicatively connected to theboiling means downstream of the same and extending in parallelism withthe boiling means, a refrigerant condenser connected to the vapor-liquidseparator, a refrigerant evaporator connected to the condenser, anabsorber vessel connected to the evaporator, an absorber coil connectedat one end thereof to the absorber vessel, a weak solution transferconduit connecting the boiling means to the other end of the absorbercoil, a rich liquid conduit supplying rich solution stored in theabsorber vessel into the vapor-liquid separator, and a rich solutiontransfer conduit connecting the vapor-liquid separator to the bottom ofthe boiling means, the improvement in which the refrigerant solutionboiling means comprises a vertically disposed pumping chamber connectedat its bottom part to the rich solution transfer conduit to be suppliedwith rich refrigerant solution thereinto, an elongated vertical boilertube disposed above said pumping chamber in vertical alignment therewithand communicating at its top with the vaporliquid separator, said boilertube being connected to the weak solution transfer conduit at its bottompart and having a diameter equal to that of the pumping chamber, and avapor lift tube communicatively connecting said pumping chamber to saidboiler tube and extending upwards into the boiler tube to open into anupper space within the boiler tube, and to provide an annular spaceabout the portion of the vapor lift pipe located within the boiler tube,said electric and gas heaters being rigidly secured by welds to thepumping chamber and the boiler tube on opposite sides thereof and atpositions such that a plane passing through the longitudinal axes of theheaters is substantially perpendicular to a plane passing through thelongitudinal axes of the separator and the boiler tube, and thelongitudinal axes of the rich and weak refrigerant solution conduitslying in the plane passing through the longitudinal axes of the boilertube and the separator.

2. The generator as claimed in claim 1, wherein the gas and electricheaters are on diametrically opposite sides of said boiler tube andpumping chamber.

3. The generator as claimed in claim 1, wherein the plane passingthrough the longitudinal axes of said heaters does not pass through thelongitudinal axis of said boiler tube and is more remote from saidseparator than said axis of the boiler tube.

4. The generator as claimed in claim 1, wherein the welds which securethe gas and electric heaters to the sides of said chamber are denser orthicker in the downward direction so as to obtain increased heatexchange relation in that direction.

5. The generator as claimed in claim 1, wherein said electric heatercomprises an outer sleeve having a longitudinal slit, said sleeve beingof a resilient sheet material, and an inner eartridge-type heatingelement resiliently gripped within said sleeve.

1. In an absorption refrigeration apparatus including a generator havingvertically elongated refrigerant solution boiling means provided withcylindrical electric and gas heaters disposed therealong, said generatorincluding a vapor-liquid separator communicatively connected to theboiling means downstream of the same and extending in parallelism withthe boiling means, a refrigerant condenser connected to the vaporliquidseparator, a refrigerant evaporator connected to the condenser, anabsorber vessel connected to the evaporator, an absorber coil connectedat one end thereof to the absorber vessel, a weak solution transferconduit connecting the boiling means to the other end of the absorbercoil, a rich liquid conduit supplying rich solution stored in theabsorber vessel into the vapor-liquid separator, and a rich solutiontransfer conduit connecting the vapor-liquid separator to the bottom ofthe boiling means, the improvement in which the refrigerant solutionboiling means comprises a vertically disposed pumping chamber connectedat its bottom part to the rich solution transfer conduit to be suppliedwith rich refrigerant solution thereinto, an elongated vertical boilertube disposed above said pumping chamber in vertical alignment therewithand communicating at its top with the vapor-liquid separator, saidboiler tube being connected to the weak solution transfer conduit at itsbottom part and having a diameter equal to that of the pumping chamber,and a vapor lift tube communicatively connecting said pumping chamber tosaid boiler tube and extending upwards into the boiler tube to open intoan upper space within the boiler tube, and to provide an annular spaceabout the portion of the vapor lift pipe located within the boiler tube,said electric and gas heaters being rigidly secured by welds to thepumping chamber and the boiler tube on opposite sides thereof and atpositions such that a plane passing through the longitudinal axes of theheaters is substantially perpendicular to a plane passing through thelongitudinal axes of the separator and the boiler tube, and thelongitudinal axes of the rich and weak refrigerant solution conduitslying in the plane passing through the longitudinal axes of the boilertube and the separator.
 2. The generator as claimed in claim 1, whereinthe gas and electric heaters are on diametrically opposite sides of saidboiler tube and pumping chamber.
 3. The generator as claimed in claim 1,wherein the plane passing through the longitudinal axes of said heatersdoes not pass through the longitudinal axis of said boiler tube and ismore remote from said separator than said axis of the boiler tube. 4.The generator as claimed in claim 1, wherein the welds which secure thegas and electric heaters to the sides of said chamber are denser orthicker in the downward direction so as to obtain increased heatexchange relation in that direction.
 5. The generator as claimed inclaim 1, wherein said electric heater comprises an outer sleeve having alongitudinal slit, said sleeve being of a resilient sheet material, andan inner cartridge-type heating element resiliently gripped within saidsleeve.